A projection display device projects light information emitted from an illumination optical system onto a screen or the like. A light source that is the main element of an illumination optical system is also a heating element, so heat radiation measure is necessary.
Accordingly, projection display devices having various types of heat radiation measure have been proposed (see, for example, PTL 1 (FIGS. 2 and 5)).
As illustrated in FIG. 5 of PTL 1, a projection display device (100) includes a light source (121), a housing (103) in which the light source (121) is accommodated, a cover plate (107) covering the housing (103), and alight source radiating member (104) attached to the cover plate (107). (Numerals enclosed by parentheses indicate symbols described in PTL 1. This is the same in the following description.)
Heat generated by the light source (121) is radiated to the air via the light source radiating member (104).
However, as illustrated in FIG. 2 of PTL 1, the size of the light source radiating member (104) is sufficiently large with respect to the size of the projection display device (100). Since the light source radiating member (104) is large, the projection display device (100) becomes necessarily large, the weight increases, and the product cost also increases.
Since a small-sized projection display device is requested, a projection display device that can be small-sized while keeping heat radiation performance is desired.